Single-lens reflex digital cameras which can convert the optical image of a subject into an electrical image signal and output the signal have been rapidly growing in popularity in recent years. With this single-lens reflex digital camera, the optical path is changed by reflecting the light incident (the image of the subject in other words) on a photographic lens using a reflecting mirror that is arranged on the photographic optical path behind the lens, and the erect image through a pentaprism and the like is guided to the optical viewfinder. As a result, the image of the subject passed through the lenses can be seen from the optical viewfinder, when the user observes a subject using the viewfinder. Therefore, normally, the position that the viewfinder optical path is formed is the fixed position of the reflecting mirror.
Meanwhile, in the case that the lenses are used for photographing, the reflecting mirror quickly changes the position thereof to retract from the photographic optical path, and by doing so, the viewfinder optical path is switched to the photographic optical path, and it will quickly return to the fixed position after photographing ends. This system is the same for a conventional silver halide camera and a digital camera, if it is a system of single-lens reflex.
One characteristic of a digital camera is that a picture can be taken when photographing while viewing a display device (for example, a liquid crystal monitor), and the image that is photographed can be checked immediately after it is taken.
However, if the system of a conventional reflecting mirror of a single-lens reflex camera is used, structurally, a monitor photographing mode that uses a liquid crystal monitor when photographing can not be realized.
Consequently, a single-lens reflex digital camera system in which photographing is possible also at the time of photographing with a liquid crystal monitor is proposed.
Patent Citation 1: Japanese Patent Laid-Open Publication No. 2001-125173